Recovering useable material from waste materials is desirable when the recovered material can be reused. For example, recycling concrete saves in material costs and further eliminates the problem of disposing of waste concrete. It is well known that when pre-mixed concrete is delivered to a job site, an amount in excess of that estimated is delivered. Thus, there is typically an amount of wet concrete remaining which must either be wasted or reclaimed.
Several devices have been produced to reclaim a variety of materials. Typical of the art are those devices listed below.
______________________________________ U.S Pat. No. Inventor Date ______________________________________ 1,460,463 O. W. Williams Jul. 3, 1923 2,807,364 W. E. Suddreth Sep. 24, 1957 3,973,093 L. C. Erickson Feb. 28, 1961 4,479,048 T. Kinoshita Oct. 23, 1984 4,616,786 R. Riker Oct. 14, 1986 ______________________________________
U.S. Pat. No. 1,460,463 discloses a grain separator wherein two rotary drums, one over the other, are utilized to separate material by size. The material is initially separated in the top drum by the use of perforations and pockets in the wall of the drum. Material collected which is in need of further processing is delivered to the lower drum where it is separated in the same fashion. The device is complex in construction. The rotary motion of the material conveyors is transmitted from a source separate from that which does controls the rotation of the drums.
U.S. Pat. No. 2,807,364 teaches a sorting device for separating screws and washers. The device includes a rotating drum which defines a plurality of perforations and hollow members which define slots. The screws pass through the perforations and the washers are passed through the slots into the hollow members. The housing of the drum is partitioned such that the screws are collected in one container and the washers are collected in another container. The device is configured to sort two specifically sized objects and is not suitable for sorting a variety of different sized materials.
U.S. Pat. No. 2,973,093 teaches a roller device with removable rolls for sorting material into fine and coarse aggregates. The rollers are elliptical in shape and each adjacent roller is 90.degree. out of phase with respect to the next roller. The material to be sorted is fed over the rotating rollers. Fine material falls between the rollers while coarse material is moved along by the motion of the rollers. The device does not provide a means for ensuring that a substantial portion of fines is removed from the material. Further, the device is limited to sorting small batches of material at a time.
U.S. Pat. No. 4,479,048 teaches a reclaiming machine for scraps of expanded foam thermoplastic material. The device is configured to receive finely crushed material scraps. The device provides a means for heating the material and moving the material along a cylinder with a screw shaft of increasing diameter such that the material is partially melted when it reaches the second end of the cylinder. The material is subsequently discharged from the device.
U.S. Pat. No. 4,616,786 teaches a plant for processing surplus concrete. The plant includes a receiving bin equipped with a conveyor screw for moving material received in the bin to a washing apparatus. The washing apparatus contains a built-in conveyor screw for conveying sand and gravel toward the right hand end during rotation of the washing apparatus. A plurality of scooping buckets are utilized to remove the sand and gravel from the end of the washing apparatus. The plant does not provide a means for separating different sized particles.
There are several reclaiming devices presently available. The devices related to the device of the present invention are: (1) the ENVIRO-MATIC manufactured by Stephens Manufacturing; (2) the ENVIRO-PORT manufactured by Enviro-port, Inc.; (3) SYSTEM 3 manufactured by J & H Equipment Co.; (4) BIBKO Recycling System manufactured by R. J. Miller Company; and (5) ROTO-RECLAIMER manufactured by Haahjem North America, Inc.
In the ENVIRO-MATIC, rock is separated first, by a vibrating screen over a screw classifier. Sand and cement fines pass through the screen into the classifier. Sand settles and is carried up the screw classifier and discharged. The cement fines pass over adjustable weir and flow into settling ponds.
In the ENVIRO-PORT, returned concrete is dumped into steel tanks where the slurry is kept in continuous agitation. A screw conveyor at the bottom of the tank removes sand and stone. The sand and stone is cleaned and stockpiled. The slurry water is pumped at controlled rate from the slurry tank into trucks.
In System 3, the waste concrete is unloaded into a receiving bin, the aggregate and sand is sorted out via a classification screw system and the slurry is received by a sand pond and silt pond wherein any sand in the slurry and the remaining components settle out.
The BIBKO system has a trough washer which is divided into pre-wash and main-wash chambers. Fresh water flows in a direction through the machine in a direction opposite to the flow of the surplus material. Separated and washed sand and gravel are discharged by the conveyor. The recycle water is collected and stored in an agitator suspension reservoir.
The ROTO-RECLAIMER is generally comprised of a rotary screen having two sections, the wash section and the sand section. The cement slurry is washed from the aggregate in the wash section. The aggregates are separated in the sand section. A spray bar delivering high volumes of water per minute extends through the entire length of the rotary screen and assists in the washing out the cement and separating the aggregates. The sand through combination of gravity and water pressure is allowed to pass through the screen and into a sand chute. The oversized product exits the rotor and fall from the rock chute. The entire unit is inclined. The material moves through the unit due to this incline. A disadvantage in using this system is that water exits through out the entire length of the unit along with material. A receiving bin extending the length of the system must be utilized to collect the material exiting through the rotary screen. Further, only gravity is relied upon to the material through the system which may cause the processing of the material more time consuming.
Therefore, it is an object of the present invention to provide a counterflow aggregate recovery apparatus for recovering reusable components of waste concrete.
Further, it is another object of the present invention to provide an apparatus which can utilized to wash and separate crushed stone aggregates or similar material.
It is yet another object of the present invention to provide an apparatus wherein the separation factor can be altered.
It is still a further object of the present invention to provide an apparatus which has a simplified construction over devices of the prior art.
It is yet another object of the present invention to provide an apparatus which provides a means for quickly and consistently moving the material through the apparatus.
It is another object of the present invention to provide an apparatus in which the material exits from either end of the apparatus thereby reducing the space necessary for a receiving bin.